Patients with HIV infection are at risk of developing psychiatric symptoms and disorders similar to those seen in the general population. Even before infection, people at risk for HIV may come from certain populations--such as injection-drug users and others with substance abuse or dependence--in whom there is a higher than average risk for psychiatric illness (Pillard, 1988; Rounsaville et al., 1982). Symptoms of anxiety and depression may be related to apprehension about disease progression and death and sadness from the loss of health, friends and income (Forstein, 1984; Nichols, 1985; Ostrow, 1987).

Several studies have found a substantial risk for DSM-III major depression and adjustment disorders with anxious or depressed mood, which may occur during asymptomatic infection (Dilley et al., 1985; Holland and Tross, 1985). In addition, patients living with an underlying mental illness--especially severe and persistent mental or mood disorders--are at a disproportionately increased risk of developing infection with HIV due to sexual and substance use behaviors (Carey et al., 2004).

Patients infected with HIV are at risk of developing dementia as a direct result of viral infection. This syndrome has been referred to by various names: HIV-associated dementia complex (HAD) (Working Group of the American Academy of Neurology AIDS Task Force, 1991), HIV encephalopathy, subacute encephalitis (Snider et al., 1983), AIDS encephalopathy and AIDS-dementia complex (Navia et al., 1986b). HIV-associated dementia is defined as acquired cognitive abnormalities in two or more domains and is associated with functional impairment and acquired motor or behavioral abnormalities, in the absence of another etiology (Table 1).